Despite growing research evidence for the importance of constructive communication to marital satisfaction, studies of the effectiveness of marital therapy in changing couples' communication have been restricted almost exclusively to behavioral approaches. Psychodynamic or insight-oriented approaches, while representing a major theoretical and clinical tradition, have not been examined for their effectiveness in helping couples improve communication in well-designed experimental studies. Moreover, marital therapy outcome studies have made little or no attempt to delineate characteristics of couples who do or do not respond to a specific therapeutic approach. The question of "which therapy for which couples" remains the least addressed and most critical diagnostic and therapeutic issue confronting the field of marital therapy. Using and experimental design, this study proposes to examine the comparative effectiveness of behavioral and insight-oriented marital therapies in helping couples improve communication, as well as attempting to identify predictors of couples' responsiveness to each approach. Ninety couples will be randomly assigned to a psychodynamic, a behavioral, or a control group. Multidiscipline, professional-level therapists with previous experenece in marital therapy will be given additional intensive training in following prepared manuals representing the two therapeutic regimens. Measurements will include two well-validated psychometric tests, an observational system utilizing videotapes, and self-report measures designed to tap attitudinal, personality, and behavioral aspects of functioning. Analyses will emphasize comparisons of relative gains on observational and self-report outcome measures across treatment groups, and identification of characteristics of those couples within each treatment group who show the most and the least improvement. A six month post-treatment follow-up will examine maintenance of relationship gains observed at termination and possible "sleeper effects" of each treatment. Ultimately, results may permit the selective employment of specific therapeutic techniques having the greatest therapeutic impact for any given couple.